Method for assembly of a gravel packing apparatus having expandable channels

ABSTRACT

A gravel packing apparatus ( 210 ) having expandable channels ( 244 ) comprises first and second tubulars ( 212, 214 ) forming an annulus therebetween. First and second base plates ( 230, 232 ) are positioned within the annulus, each base plate ( 230, 232 ) having at least one receiving notch ( 234, 236 ). An expandable channel ( 244 ) having first and second configurations extends between the respective receiving notches ( 234, 236 ) of the first and second base plates ( 230, 232 ) within the annulus. Each expandable channel ( 244 ) initially has a flexible hose ( 252 ) disposed therein such that when the flexible hose ( 252 ) is pressurizing, the expandable channels ( 244 ) are expanded from the first configuration to a second configuration, thereby forming slurry passageways in the gravel packing apparatus ( 210 ).

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates, in general, to preventing the production of particulate materials through a wellbore traversing an unconsolidated or loosely consolidated subterranean formation and, in particular, to a method for assembly of a gravel packing apparatus having expandable channels.

BACKGROUND OF THE INVENTION

[0002] Without limiting the scope of the present invention, its background is described with reference to the production of hydrocarbons through a wellbore traversing an unconsolidated or loosely consolidated formation, as an example.

[0003] It is well known in the subterranean well drilling and completion art that particulate materials such as sand may be produced during the production of hydrocarbons from a well traversing an unconsolidated or loosely consolidated subterranean formation. Numerous problems may occur as a result of the production of such particulate. For example, the particulate causes abrasive wear to components within the well, such as tubing, pumps and valves. In addition, the particulate may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate matter is produced to the surface, it must be removed from the hydrocarbon fluids by processing equipment at the surface.

[0004] One method for preventing the production of such particulate material to the surface is gravel packing the well adjacent the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a work string to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a particulate material known as gravel is then pumped down the work string and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.

[0005] The liquid carrier either flows into the formation or returns to the surface by flowing through the sand control screen or both. In either case, the gravel is deposited around the sand control screen to form a gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the particulate carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of particulate materials from the formation.

[0006] It has been found, however, that a complete gravel pack of the desired production interval is difficult to achieve particularly in long or inclined/horizontal production intervals. These incomplete packs are commonly a result of the liquid carrier entering a permeable portion of the production interval causing the gravel to form a sand bridge in the annulus. Thereafter, the sand bridge prevents the slurry from flowing to the remainder of the annulus which, in turn, prevents the placement of sufficient gravel in the remainder of the annulus.

[0007] Prior art devices and methods have been developed which attempt to overcome this sand bridge problem. For example, attempts have been made to use devices having perforated shunt tubes or bypass conduits that extend along the length of the sand control screen to provide an alternate path for the fluid slurry around the sand bridge. It has been found, however, that shunt tubes installed on the exterior of sand control screens are susceptible to damage during installation and may fail during a gravel pack operation. In addition, it has been found, that it is difficult and time consuming to make all of the necessary fluid connections between the numerous joints of shunt tubes required for typical production intervals.

[0008] Therefore a need has arisen for an apparatus and method for gravel packing a production interval traversed by a wellbore that overcomes the problems created by sand bridges. A need has also arisen for such an apparatus that is not susceptible to damage during installation or failure during use. Further, a need has arisen for such an apparatus that is not difficult or time consuming to assemble.

SUMMARY OF THE INVENTION

[0009] The present invention disclosed herein comprises method for assembly of a gravel packing apparatus having expandable channels that is used for gravel packing a production interval of a wellbore that traverses an unconsolidated or loosely consolidated formation and that overcomes the problems created by the development of a sand bridge between a sand control screen and the wellbore. Importantly, the method of the present invention results in a gravel packing apparatus that is not susceptible to damage during installation or failure during use and is not difficult or time consuming to assemble.

[0010] The gravel packing apparatus of the present invention comprises an outer tubular forming a first annulus with the wellbore and an inner tubular disposed within the outer tubular forming a second annulus therebetween. Typically, the inner tubular is positioned around a sand control screen. Together, the sand control screen and the apparatus of the present invention are assembled at the surface and run downhole to a location proximate the production interval. One or more portions of the side wall of the outer tubular are axially extending production sections that include a plurality of openings. Other portions of the side wall of the outer tubular are axially extending nonproduction sections that include a plurality of outlets. Similarly, portions of the side wall of the inner tubular are axially extending production sections that are substantially circumferentially aligned with the production sections of the outer tubular. The production sections of the inner tubular have a plurality of openings therethrough.

[0011] In the volume within the second annulus between the nonproduction sections of the outer tubular and the inner tubular there are one or more channels that define axially extending slurry passageways with the nonproduction section of the outer tubular. The volume within the second annulus between the production sections of the outer and inner tubulars are axially extending production pathways. The channels prevent fluid communication between the production pathways and the slurry passageways within the second annulus.

[0012] As such, when a fluid slurry containing gravel is injected through the slurry passageways, the fluid slurry exits the slurry passageways through the outlets in the outer tubular leaving a first portion of the gravel in the first annulus. Thereafter, the fluid slurry enters the openings in the production sections of the outer tubular leaving a second portion of the gravel in the production pathways. Thus, when formation fluids are produced, the formation fluids travel radially through the production pathways by entering the production pathways through the openings in the outer tubular and exiting the production pathways through the openings in the inner tubular. The formation fluids pass through the first portion of the gravel in the first annulus prior to entry into the production pathways, which contains the second portion of the gravel, both of which filter out the particulate materials in the formation fluids.

[0013] Broadly stated, the method of assembly of the present invention involves expanding an expandable channel in an annulus between the two tubulars by supporting the expandable channel having a flexible hose disposed therein in the annulus between two tubulars, pressurizing the flexible hose, expanding the expandable channel from a first configuration to a second configuration and removing the flexible hose.

[0014] More specifically, the method of the present invention involves providing a first tubular, installing first and second base plates proximate each end of the first tubular, each base plate having a receiving notch, extending an expandable channel in a first configuration between the receiving notches of the first and second base plates, disposing a flexible hose within the expandable channel, positioning a second tubular substantially around the first and second base plates and the expandable channel, pressurizing the flexible hose, expanding the expandable channel from the first configuration to a second configuration and removing the flexible hose.

[0015] The method may also involve spot welding the expandable channel to the first tubular, welding the first and second base plates to the first tubular, welding the second tubular to the first and second base plates and welding the expandable channel to the receiving notches of the first and second base plates after the expandable channel has been expanded.

[0016] In addition, the method may involve expanding side sections of the expandable channel from a first angle relative to a web section of the expandable channel to a second angle that is larger than the first angle. For example, the first angle may be an acute angle and the second angle may be an obtuse angle. The expansion process is achieved by elastically and plastically deforming the expandable channel. The expansion process preferably results in the end portion of the side sections of the expandable channel coming into intimate contact with the interior of the second tubular such that a substantially fluid tight slurry passageway is created.

[0017] Once each section of the gravel packing apparatus of the present invention is assembled, more than one section of the gravel packing apparatus of the present invention must commonly be coupled together to achieve a length sufficient to gravel pack an entire production interval. In such cases, multiple sections of the apparatus of the present invention are coupled together, for example, via a threaded connection. Also, in such cases, the slurry passageways of the various sections are in fluid communication with one another allowing an injected fluid slurry to flow from one such apparatus to the next, while the production pathways of the various sections are in fluid isolation from one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:

[0019]FIG. 1 is a schematic illustration of an offshore oil and gas platform operating a plurality of gravel packing apparatuses having expandable channels of the present invention;

[0020]FIG. 2 is partial cut away view of a gravel packing apparatus having expandable channels of the present invention in position around a sand control screen;

[0021]FIG. 3 is partial cut away view of a gravel packing apparatus having expandable channels of the present invention in position around a sand control screen;

[0022]FIG. 4 is a side view of portions of two outer tubulars of a gravel packing apparatus having expandable channels of the present invention that are coupled together;

[0023]FIG. 5 is a side view of portions of two inner tubulars of a gravel packing apparatus having expandable channels of the present invention that are coupled together;

[0024]FIG. 6 is a perspective view partially in phantom of a gravel packing apparatus having expandable channels of the present invention prior to the expansion of the channels;

[0025]FIG. 7 is a cross sectional view of the gravel packing apparatus having expandable channels of the present invention taken along line 7-7 of FIG. 6;

[0026]FIG. 8 is a perspective view partially in phantom of a gravel packing apparatus having expandable channels of the present invention after the expansion of the channels; and

[0027]FIG. 9 is a cross sectional view of the gravel packing apparatus having expandable channels of the present invention taken along line 9-9 of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0028] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.

[0029] Referring initially to FIG. 1, several apparatuses for gravel packing an interval of a wellbore formed using the method of the present invention and operating from an offshore oil and gas platform are schematically illustrated and generally designated 10. A semi-submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16. A subsea conduit 18 extends from deck 20 of platform 12 to wellhead installation 22 including blowout preventers 24. Platform 12 has a hoisting apparatus 26 and a derrick 28 for raising and lowering pipe strings such as work string 30.

[0030] A wellbore 32 extends through the various earth strata including formation 14. A casing 34 is cemented within wellbore 32 by cement 36. Work string 30 includes various tools including apparatuses 38, 40, 42 for gravel packing an interval of wellbore 32 adjacent to formation 14 between packers 44, 46 which is identified as annular region 48. When it is desired to gravel pack annular region 48, work string 30 is lowered through casing 34 until apparatuses 38, 40, 42 are positioned adjacent to formation 14 including perforations 50. Thereafter, a fluid slurry including a liquid carrier and a particulate material such as gravel is pumped down work string 30.

[0031] During this process, portions of the fluid slurry exit each apparatus 38, 40, 42 such that the fluid slurry enters annular region 48. Once in annular region 48, a portion the gravel in the fluid slurry is deposited therein. Some of the liquid carrier may enter formation 14 through perforation 50 while the remainder of the fluid carrier, along with some of the gravel, reenters certain sections of apparatuses 38, 40, 42 depositing gravel in those sections. As sand control screens (not pictured) are positioned within or are integral with apparatuses 38, 40, 42, the gravel remaining in the fluid slurry is disallowed from further migration. The liquid carrier, however, can travel through the sand control screens, into work string 30 and up to the surface in a known manner, such as through a wash pipe and into the annulus 52 above packer 44. The fluid slurry is pumped down work string 30 through apparatuses 38, 40, 42 until annular section 48 surrounding apparatuses 38, 40, 42 and portions of apparatuses 38, 40, 42 are filled with gravel.

[0032] Alternatively, instead of injecting the entire stream of fluid slurry into apparatuses 38, 40, 42, all or a portion of the fluid slurry could be injected directly into annular region 48 in a known manner such as through a crossover tool (not pictured) which allows the slurry to travel from the interior of work string 30 to the exterior of work string 30. Again, once this portion of the fluid slurry is in annular region 48, a portion the gravel in the fluid slurry is deposited in annular region 48. Some of the liquid carrier may enter formation 14 through perforation 50 while the remainder of the fluid carrier along with some of the gravel enters certain sections of apparatuses 38, 40, 42 filling those sections with gravel. The sand control screens (not pictured) within apparatuses 38, 40, 42 disallow further migration of the gravel but allows the liquid carrier to travel therethrough into work string 30 and up to the surface. If the fluid slurry is injected directly into annular region 48 and a sand bridge forms, the fluid slurry is diverted into apparatuses 38, 40, 42 to bypass this sand bridge such that a complete pack can nonetheless be achieved. The fluid slurry entering apparatuses 38, 40, 42 may enter apparatuses 38, 40, 42 proximate work string 30 or may enter apparatuses 38, 40, 42 from annular region 48 via one or more inlets on the exterior of one or more of the apparatuses 38, 40, 42. These inlets may include pressure actuated devices, such as valves, rupture disks and the like disposed therein to regulate the flow of the fluid slurry therethrough.

[0033] Even though FIG. 1 depicts a vertical well, it should be noted by one skilled in the art that the gravel packing apparatuses of the present invention are equally well-suited for use in deviated wells, inclined wells or horizontal wells. Also, even though FIG. 1 depicts an offshore operation, it should be noted by one skilled in the art that the gravel packing apparatuses of the present invention are equally well-suited for use in onshore operations.

[0034] In addition, it should be apparent to those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure.

[0035] Referring now to FIG. 2, therein is depicted a partial cut away view of a gravel packing apparatus having expandable channels that is manufactured using the method of the present invention and that is generally designated 60. Apparatus 60 has an outer tubular 62. Portions of the side wall of outer tubular 62 are axially extending production sections 64 that includes a plurality of openings 66. Other portions of the side wall of outer tubular 62 are axially extending nonproduction sections 68, only one of which is visible, that includes outlets 70, only one of which is visible. For reasons that will become apparent to those skilled in the art, the density of openings 66 within production sections 64 of outer tubular 62 is much greater than the density of outlets 70 in nonproduction sections 68 of outer tubular 62. Also, it should be noted by those skilled in the art that even though FIG. 2 has depicted openings 66 and outlets 70 as being circular, other shaped openings may alternatively be used without departing from the principles of the present invention. Likewise, even though FIG. 2 has depicted openings 66 as being the same size as outlets 70, openings 66 could alternatively be larger or smaller than outlets 70 without departing from the principles of the present invention. In addition, the exact number, size and shape of openings 66 are not critical to the present invention, so long as sufficient area is provided for fluid production therethrough and the integrity of outer tubular 62 is maintained.

[0036] Disposed within outer tubular 62 is a sand control screen 72. Sand control screen 72 includes a base pipe 74 that has a plurality of openings 76 which allow the flow of production fluids into the production tubing. The exact number, size and shape of openings 76 are not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of base pipe 74 is maintained.

[0037] Spaced around base pipe 74 is a plurality of ribs 78. Ribs 78 are generally symmetrically distributed about the axis of base pipe 74. Ribs 78 are depicted as having a cylindrical cross section, however, it should be understood by one skilled in the art that ribs 78 may alternatively have a rectangular or triangular cross section or other suitable geometry. Additionally, it should be understood by one skilled in the art that the exact number of ribs 78 will be dependant upon the diameter of base pipe 74 as well as other design characteristics that are well known in the art.

[0038] Wrapped around ribs 78 is a screen wire 80. Screen wire 80 forms a plurality of turns, such as turn 82, turn 84 and turn 86. Between each of the turns is a gap through which formation fluids flow. The number of turns and the gap between the turns are determined based upon the characteristics of the formation from which fluid is being produced and the size of the gravel to be used during the gravel packing operation. Together, ribs 78 and screen wire 80 may form a sand control screen jacket that is attached to base pipe 74 by welding or other suitable technique.

[0039] Disposed within an annulus 88 between outer tubular 62 and sand control screen 72 are channels 90, only one of which is visible. Each channel 90 includes a web 92 and a pair of oppositely disposed sides 94 that are expanded such that the ends of sides 94 come into contact with the inner surface of outer tubular 62, as explained in greater detail below. Channels 90 are substantially aligned with outlets 70 of outer tubular 62. Together, channels 90 and nonproduction sections 68 of outer tubular 62 define slurry passageways 96, only one of which is visible. Production pathways 98 are defined by production sections 64 of outer tubular 62 between channels 90. Slurry passageways 96 and production pathways 98 are in fluid isolation from one another within annulus 88.

[0040] It should be understood by those skilled in the art that other types of filter media may be used in conjunction with the gravel packing apparatus having expandable channels of the present invention. For example, as seen in FIG. 3, therein is depicted a partial cut away view of a gravel packing apparatus having expandable channels of the present invention that is positioned around a sand control screen and that is generally designated 100. Apparatus 100 has an outer tubular 102. Portions of the side wall of outer tubular 102 are axially extending production sections 104 that include a plurality of openings 106. Other portions of the side wall of outer tubular 102 are axially extending nonproduction sections 108 that includes outlets 110.

[0041] Disposed within outer tubular 102 is a sand control screen assembly 112. Sand control screen assembly 112 includes a base pipe 114 that has a plurality of openings 116 which allow the flow of production fluids into the production tubing. Positioned around base pipe 114 is a fluid-porous, particulate restricting, sintered metal material such as a plurality of layers of a wire mesh that are sintered together to form a porous sintered wire mesh screen 118. Screen 118 is designed to allow fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough. Positioned around screen 118 is a screen housing 120 that has a plurality of openings 122 which allow the flow of production fluids therethrough. The exact number, size and shape of openings 122 is not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of housing 120 is maintained.

[0042] Disposed within an annulus 124 between outer tubular 102 and sand control screen assembly 112 is a pair of channels 126, only one channel 126 being visible. Each channel 126 includes a web 128 and a pair of sides 130 that are expanded such that the ends of sides 130 come in contact with the inner surface of outer housing 102. Accordingly, each channel 126 provides substantial circumferential fluid isolation between production sections 104 and nonproduction sections 108 of outer tubular 102 and defines the circumferential boundary between slurry passageways 132, having outer radial boundaries defined by nonproduction sections 108 of outer tubular 102 and production pathways 134, having outer radial boundaries defined by production sections 104 of outer tubular 102.

[0043] Referring now to FIGS. 4 and 5, therein are depicted portions of two sections of outer tubulars designated 140, 142 and corresponding portions of two sections of inner tubular designated 144, 146, respectively. For convenience of illustration, outer tubulars 140, 142 have been removed from inner tubulars 144, 146 to describe the flow of a fluid slurry therein. It should be noted that outer tubulars 140, 142 may represent a tubular such as outer tubular 102 of FIG. 3 or outer tubular 62 of FIG. 2 and inner tubulars 144, 146 may represent a tubular such as screen housing 120 of FIG. 3 or screen wire 80 of FIG. 2. Outer tubular 140 has two axially extending production sections 148, 150 each including a plurality of openings 152. Outer tubular 140 also has two axially extending nonproduction sections, only nonproduction section 154 being visible in FIG. 4. Each nonproduction section includes several outlets 158. Likewise, outer tubular 142 has two axially extending production sections, only production section 160 being visible in FIG. 4. Each production section includes a plurality of openings 164. Outer tubular 142 also has two axially extending nonproduction sections 166, 168, each of which includes several outlets 170.

[0044] As should become apparent to those skilled in the art, even though FIG. 4 depicts outer tubular 140 and outer tubular 142 at a ninety-degree circumferential phase shift relative to one another, any degree of circumferential phase shift is acceptable using the present invention as the relative circumferential positions of adjoining sections of the gravel packing apparatuses of the present invention do not affect the operation of the present invention. As such, the mating of adjoining sections of the gravel packing apparatuses of the present invention is substantially similar to mating typical joints of pipe to form a pipe string requiring no special coupling tools or techniques. For example, in the illustrated embodiment, a collar 171 is used to couple outer tubulars 140, 142 which may use threading, welding, a combination of the two or other suitable techniques to achieve the desired attachment.

[0045] In the illustrated embodiment, inner tubular 144 has two axially extending production sections 172, 174 each including a plurality of openings 176. Positioned on inner tubular 144 is a pair of channels, only channel 178 being visible in FIG. 5. A base plate 180 is securably attached to inner tubular 144 by welding or other suitable technique. The channels are securably attached to base plate 180 by welding or other suitable technique and may be attached to inner tubular 144 by spot welding if desired. Inner tubular 144 includes an end section 182. Likewise, inner tubular 146 has two axially extending production sections, only production section 184 being visible in FIG. 5. Each production section includes a plurality of openings 186. Positioned on inner tubular 146 is a pair of channels 188, 190 and a base plate 192. Base plate 192 is securably attached to inner tubular 146. Channels 188, 190 are securably attached to base plate 192 and may be attached to inner tubular 146. Inner tubular 146 includes an end section 194. A coupling 196 is used to couple end sections 182, 194 by threading, welding, sliding, a combination of those techniques or other suitable technique.

[0046] In the illustrated embodiment, inner tubulars 144, 146 would be positioned within outer tubulars 140, 142 such that the nonproduction sections of outer tubular 140 are circumferentially aligned with the channels of inner tubular 144. Likewise, the nonproduction sections of outer tubular 142 are circumferentially aligned with channels 188, 190 of inner tubular 146.

[0047] In these configurations, the channels of inner tubular 144 together with the nonproduction sections of outer tubular 140 define slurry passageways 200, only one of which being visible, that are in substantial fluid isolation from the production pathways defined by the portion of the annulus between inner tubular 144 and outer tubular 140 circumferentially aligned with production sections 148, 150 of outer tubular 140.

[0048] Channels 188, 190 together with nonproduction sections 166, 168 of outer tubular 142 define slurry passageways 202 that are in substantial fluid isolation from the production pathways defined by the portion of the annulus between inner tubular 146 and outer tubular 142 circumferentially aligned with the production sections of outer tubular 142.

[0049] Importantly, slurry passageways 200 and slurry passageways 202 are in fluid communication with one another such that a fluid slurry may travel in and between these passageways from one section of the gravel packing apparatuses of the present invention to the next. Specifically, an annular transition region 204 exists between outer tubulars 140, 142 and inner tubulars 144, 146 that allows the fluid slurry to travel downwardly from slurry passageways 200 through annular transition region 204 into slurry passageways 202. As such, regardless of the circumferential orientation of inner tubular 144 relative to inner tubular 146, the fluid slurry will travel down through each section of the gravel packing apparatuses of the present invention.

[0050] As should be apparent from FIGS. 2-5, the gravel packing apparatuses of the present invention may have a variety of configurations including configurations having two slurry passageways. Other configuration having other numbers of slurry passageways both greater than and less than two are also possible and are considered within the scope of the present invention.

[0051] Referring next to FIG. 6, therein is depicted a gravel packing apparatus having expandable channels during the assembly process of the present invention that is generally designated 210. Gravel packing apparatus 210 includes an inner tubular 212 and an outer tubular 214 depicted in phantom for convenience of illustration. For convenience of description, FIGS. 6-9 will describe gravel packing apparatus 210 as having a single slurry passageway. As described above, inner tubular 212 has perforated section 216 that allows for production therethrough and end sections 218, 220 that provide for the coupling together of multiple joints of inner tubulars 212. Outer tubular 214 includes production section 222 having high density openings 224 therein and nonproduction section 226 having relatively low density outlets 228 therein.

[0052] During the assembly process, base plates 230, 232 are installed proximate end sections 218, 220 of inner tubular 212. Preferably base plates 230, 232 are welded to inner tubular 212, however, other attachment techniques could alternatively be used. Base plates 230, 232 respectively have receiving notches 234, 236 that are circumferentially aligned with one another. As best seen in FIG. 7, receiving notch 234 has a base section 238 and a pair of oppositely disposed side sections 240, 242. In the illustrated embodiment, the angle of side sections 240, 242 relative to base section 238 is greater than ninety degrees, however, other angles both larger and smaller than that depicted are contemplated and are considered within the scope of the present invention. The exact angle selected will be based upon a variety of factors including the desired flow volume through the slurry passageway of gravel packing apparatus 210, the thickness of the annulus between inner tubular 212 and outer tubular 214, the desired shape of the expanded channels, as discussed below, and the like.

[0053] Once base plates 230, 232 are attached to inner tubular 212 with receiving notches 234, 236 circumferentially aligned with one another, an expandable channel 244 is positioned between base plates 230, 232 within receiving notches 234, 236. As best seen in FIG. 7, expandable channel 244 has a web section 246 and a pair of oppositely disposed side sections 248, 250. Expandable channel 244 is initially in the configuration shown in FIG. 7 wherein side sections 248, 250 form an acute angle relative to web section 246. In this configuration, side sections 248, 250 do not interfere with the installation of outer tubular 214 as explained below. Expandable channel 244 is constructed from a formable sheet metal such as, for example, a stainless steel having a thickness of between about twenty and one hundred thousandths of an inch. Once expandable channel 244 is properly positioned, expandable channel 244 may be spot welded or otherwise secured to inner tubular 212 such that expandable channel 244 will not move during the installation of outer tubular 214 or during its expansion.

[0054] A flexible hose 252 is then placed within expandable channel 244. Preferably, flexible hose 252 is designed to lay flat within expandable channel 244 and expand under pressure. For example, flexible hose 252 may be a single jacket rubber lined hose, a double jacket rubber lined hose or the like, wherein the jackets are a woven synthetic material such as polyester. Flexible hose 252 should be rated for between 500 and 1000 psi depending upon the pressure required to expand expandable channel 244.

[0055] Once flexible hose 252 is in place, outer tubular 214 may be installed around base plates 230, 232 and expandable channel 244. In the illustrated embodiment, outer tubular 214 extends between base plates 230, 232 and may be securably attached to base plates 230, 232 by welding or other suitable technique at this time. To assure the concentricity of outer tubular 214 relative to inner tubular 212 centralizers 254 may be used.

[0056] Once outer tubular 214 is in position, flexible hose 252 may be connected to a fluid pressure source (not pictured). Flexible hose 252 is then pressurized such that the exterior surface of flexible hose 252 contacts the inner surfaces of expandable channel 244 and nonproduction section 226 of outer tubular 214 taking the shape thereof. The pressure within flexible hose 252 is then increased such that side sections 248, 250 of expandable channel 244 begin to flex relative to web section 246. This flexure continues causing elastic and plastic deformation of expandable channel 244 until, as best seen in FIGS. 8 and 9, side sections 248, 250 of expandable channel 244 contact side sections 240, 242 of receiving notches 234, 236 of respective base plates 230, 232. Side sections 240, 242 of receiving notches 234, 236 substantially define the maximum desirable flexure of side sections 248, 250 of expandable channel 244. In the illustrated embodiment, this maximum travel creates an obtuse angle between side sections 248, 250 of expandable channel 244 and web section 246.

[0057] During the expansion process, the ends of side sections 248, 250 come into contact with the interior of outer tubular 214. In fact, intimate contact is created between the ends of side sections 248, 250 and the interior of outer tubular 214 providing a substantially fluid tight metal to metal seal therebetween. Once the expansion process is completed, the pressure within flexible hose 252 is relieved and flexible hose 252 may be removed from the newly expanded expandable channel 244. Once the force created by the pressurized flexible hose 252 is removed, the elastic portion of the deformation of expandable channel 244 operates to increase the force between the ends of side sections 248, 250 and the interior of outer tubular 214 thereby enhancing the substantially fluid tight metal to metal contact therebetween.

[0058] Once flexible hose 252 has been removed from expandable channel 244, expandable channel 244 may be welded within receiving notches 234, 236. In addition, outer tubular 214 may be securably attached to base plates 230, 232 by, for example, welding or other suitable technique if this attachment process was not previously accomplished. Following the assembly of each joint of gravel packing apparatus 210, these joints may be attached together as described herein to form stands or strings of gravel packing apparatuses 210.

[0059] It should be noted by those skilled in the art that the above described expansion process is suitable for use in expanding any number of expandable channels positioned between an inner tubular and an outer tubular. In cases where multiple channels are desired and installed, each of the flexible hoses disposed within each of the expandable channels should be connected to the same fluid pressure source and preferably arranged in parallel. In this configuration, the expansion of the expandable channels occurs simultaneously and substantially uniformly within the outer tubular such that the circumferential forces within the outer tubular are balanced.

[0060] In operation, the gravel packing apparatuses of the present invention are placed with an interval of a wellbore and used to distribute the fluid slurry to various locations within the interval to be gravel packed by injecting the fluid slurry into the slurry passageways created by the channels and the outer tubular and through the transition sections between joints of the apparatuses. The fluid slurry exits through the various outlets along the slurry passageway and enters the annulus between the gravel packing apparatuses and the wellbore which may be cased or uncased. Once in this annulus, a portion of the gravel in the fluid slurry is deposited around the string of gravel packing apparatuses in the annulus such that the gravel migrates both circumferentially and axially from the outlets. This process progresses along the entire length of the string of gravel packing apparatuses such that the annular area becomes completely packed with the gravel. In addition, a portion of the fluid slurry enters the opening in the production sections of the outer tubular which provides for the deposit of a portion of the gravel from the fluid slurry in the production pathways between the outer tubular and the inner tubular. Again, this process progresses along the entire length of the apparatus such that each production pathway becomes completely packed with the gravel. Once both the annulus and the production pathways are completely packed with gravel, the gravel pack operation may cease.

[0061] In some embodiments of the present invention, the fluid slurry may not initially be injected into the slurry passageways. Instead, the fluid slurry is injected directly into the annulus between the gravel packing apparatuses and the wellbore. The annulus serves as the primary path for the fluid slurry containing gravel as the fluid slurry seeks the path of least resistance. Under ideal conditions, the fluid slurry travels in the annulus until the annulus is completely packed with gravel. In addition, the fluid slurry enters the production pathways of the gravel packing apparatuses such that these areas are also completely packed with gravel.

[0062] It has been found, however, that sand bridges commonly form during a gravel packing operation. These sand bridges are bypassed using the gravel packing apparatuses of the present invention by first allowing the fluid slurry to pass through the outer tubular into the production pathways of the gravel packing apparatuses, bypassing the sand bridge and then returning to the annular interval through the outer tubular to complete the gravel packing process. These pathways are considered the secondary path for the fluid slurry. If a sand bridge forms in the secondary paths prior to completing the gravel packing operation, then the fluid slurry enters the slurry passageways formed by the expandable channels and progresses through the gravel packing apparatuses as described above. In this process, the expandable channels are considered the tertiary path for the fluid slurry. It should be understood by those skilled in the art that even though the paths have been described as being primary, secondary and tertiary, the fluid slurry may simultaneously travel through each of these paths.

[0063] Once the gravel pack is completed and the well is brought on line, formation fluids that are produced into the gravel packed interval must travel through the gravel pack in the annulus, then enter the production pathways through the openings in the outer tubular where the formation fluids pass through the gravel pack between the outer tubular and the inner tubular before traveling through the sand control screen and into the production tubing. As such, the gravel packing apparatus of the present invention allows for a complete gravel pack of an interval so that particulate materials in the formation fluid are filtered out.

[0064] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments. 

What is claimed is:
 1. A method for assembling a gravel packing apparatus comprising the steps of: providing a first tubular; installing first and second base plates proximate each end of the first tubular, each base plate having a receiving notch; extending an expandable channel in a first configuration between the receiving notches of the first and second base plates; disposing a flexible hose within the expandable channel; positioning a second tubular substantially around the first and second base plates and the expandable channel; pressurizing the flexible hose; expanding the expandable channel from the first configuration to a second configuration; and removing the flexible hose.
 2. The method as recited in claim 1 further comprising after the step of extending an expandable channel in a first configuration between the receiving notches of the first and second base plates, the step of spot welding the expandable channel to the first tubular.
 3. The method as recited in claim 1 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel from a first angle relative to a web section of the expandable channel to a second angle that is larger than the first angle.
 4. The method as recited in claim 1 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel from an acute angle relative to a web section of the expandable channel to an obtuse angle.
 5. The method as recited in claim 1 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel relative to a web section of the expandable channel such that the end portion of the side sections contacts the second tubular.
 6. The method as recited in claim 1 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises plastically deforming the expandable channel.
 7. The method as recited in claim 1 further comprising the steps of: welding the first and second base plates to the first tubular; welding the second tubular to the first and second base plates; and welding the expandable channel to the receiving notches of the first and second base plates after the expandable channel has been expanded.
 8. The method as recited in claim 1 further comprising placing centralizers on the first tubular such that when the second tubular is positioned substantially around the first and second base plates and the expandable channel, the second tubular is substantially concentric with the first tubular.
 9. A method for assembling a gravel packing apparatus comprising the steps of: providing a first tubular; installing first and second base plates proximate each end of the first tubular, each base plate having a plurality of receiving notches; extending a plurality of expandable channels each in a first configuration between respective pairs of the receiving notches of the first and second base plates; disposing a flexible hose within each of the expandable channels; positioning a second tubular substantially around the first and second base plates and the expandable channels; simultaneously pressurizing each of the flexible hoses; expanding each of the expandable channels from the first configuration to a second configuration; and removing the flexible hoses.
 10. The method as recited in claim 9 further comprising after the step of extending a plurality of expandable channels each in a first configuration between respective pairs of the receiving notches of the first and second base plates, the step of spot welding each of the expandable channels to the first tubular.
 11. The method as recited in claim 9 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding respective side sections of the expandable channels from a first angle relative to web sections of the expandable channels to a second angle that is larger than the first angle.
 12. The method as recited in claim 9 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding respective side sections of the expandable channels from an acute angle relative to web sections of the expandable channels to an obtuse angle.
 13. The method as recited in claim 9 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding respective side sections of the expandable channels relative to web sections of the expandable channels such that the end portion of the side sections contacts the second tubular.
 14. The method as recited in claim 9 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises plastically deforming the expandable channels.
 15. The method as recited in claim 9 further comprising the steps of: welding the first and second base plates to the first tubular; welding the second tubular to the first and second base plates; and welding the expandable channels to the receiving notches of the first and second base plates after the expandable channels have been expanded.
 16. The method as recited in claim 9 further comprising placing centralizers on the first tubular such that when the second tubular is positioned substantially around the first and second base plates and the expandable channels, the second tubular is substantially concentric with the first tubular.
 17. A method for expanding an expandable channel in an annulus between two tubulars comprising the steps of: supporting the expandable channel in a first configuration having a flexible hose disposed within the expandable channel in the annulus between two tubulars; pressurizing the flexible hose; expanding the expandable channel from the first configuration to a second configuration; and removing the flexible hose.
 18. The method as recited in claim 17 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel from a first angle relative to a web section of the expandable channel to a second angle that is larger than the first angle.
 19. The method as recited in claim 17 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel from an acute angle relative to a web section of the expandable channel to an obtuse angle.
 20. The method as recited in claim 17 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding side sections of the expandable channel relative to a web section of the expandable channel such that the end portion of the side sections contacts the second tubular.
 21. The method as recited in claim 17 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises plastically deforming the expandable channel.
 22. The method as recited in claim 17 further comprising placing centralizers between the two tubulars to assure substantial concentricity.
 23. A method for assembling a gravel packing apparatus comprising the steps of: providing first and second inner tubulars; installing first and second base plates proximate both ends of the first and second inner tubulars, each base plate having a receiving notch; extending an expandable channel in a first configuration between the receiving notches of the first and second base plates on each of the first and second inner tubulars; disposing a flexible hose within each of the expandable channels; positioning first and second outer tubulars substantially around the first and second base plates and the expandable channel of the respective first and second inner tubulars; pressurizing each of the flexible hoses; expanding each of the expandable channels from the first configuration to a second configuration; removing the flexible hoses; and coupling the first inner tubular to the second inner tubular and the first outer tubular to the second outer tubular.
 24. The method as recited in claim 23 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding side sections of the expandable channels from a first angle relative to web sections of the expandable channels to a second angle that is larger than the first angle.
 25. The method as recited in claim 23 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding side sections of the expandable channels from an acute angle relative to web sections of the expandable channels to an obtuse angle.
 26. The method as recited in claim 23 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises expanding side sections of the expandable channels relative to web sections of the expandable channels such that the end portion of the side sections contacts the respective outer tubular.
 27. The method as recited in claim 23 wherein the step of expanding each of the expandable channels from the first configuration to the second configuration further comprises plastically deforming each of the expandable channels.
 28. A method for assembling a gravel packing apparatus comprising the steps of: providing a first tubular; installing first and second base plates proximate each end of the first tubular, each base plate having a receiving notch; extending an expandable channel in a first configuration between the receiving notches of the first and second base plates; disposing a flexible hose within the expandable channel; positioning a second tubular substantially around the first and second base plates and the expandable channel; pressurizing the flexible hose; expanding the expandable channel from the first configuration to a second configuration such that side sections of the expandable channel expand relative to a web section of the expandable channel causing end portions of the side sections to contact the second tubular; and removing the flexible hose.
 29. The method as recited in claim 28 further comprising after the step of extending an expandable channel in a first configuration between the receiving notches of the first and second base plates, the step of spot welding the expandable channel to the first tubular.
 30. The method as recited in claim 28 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding the side sections of the expandable channel from a first angle relative to the web section of the expandable channel to a second angle that is larger than the first angle.
 31. The method as recited in claim 28 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises expanding the side sections of the expandable channel from an acute angle relative to the web section of the expandable channel to an obtuse angle.
 32. The method as recited in claim 28 wherein the step of expanding the expandable channel from the first configuration to the second configuration further comprises plastically deforming the expandable channel.
 33. The method as recited in claim 28 further comprising the steps of: welding the first and second base plates to the first tubular; welding the second tubular to the first and second base plates; and welding the expandable channel to the receiving notches of the first and second base plates after the expandable channel has been expanded.
 34. The method as recited in claim 28 further comprising placing centralizers on the first tubular such that when the second tubular is positioned substantially around the first and second base plates and the expandable channel, the second tubular is substantially concentric with the first tubular.
 35. An apparatus for gravel packing an interval of a wellbore comprising: first and second tubulars forming an annulus therebetween; first and second base plates positioned within the annulus, each base plate having a receiving notch; and an expandable channel having first and second configurations extending between the receiving notches of the first and second base plates within the annulus, the expandable channel initially having a flexible hose disposed therein such that when the flexible hose is pressurized, the expandable channel is expanded from the first configuration to a second configuration.
 36. The apparatus as recited in claim 35 wherein the expandable channel is spot welded to the first tubular.
 37. The apparatus as recited in claim 35 wherein the expandable channel has a pair of oppositely disposed sides and a web therebetween and wherein angle between the sides and the web is smaller in the first configuration as compared to the second configuration.
 38. The apparatus as recited in claim 35 wherein the expandable channel has a pair of oppositely disposed sides and a web therebetween and wherein angle between the sides and the web is acute in the first configuration and obtuse in the second configuration.
 39. The apparatus as recited in claim 35 wherein the expandable channel has a pair of oppositely disposed sides and a web therebetween and wherein end portions of the side sections contact the second tubular when the expandable channel is in the second configuration.
 40. The apparatus as recited in claim 35 wherein the expandable channel is plastically deformed from the first configuration to the second configuration.
 41. The apparatus as recited in claim 35 wherein the first and second base plates are welded to the first tubular, wherein the second tubular is welded to the first and second base plates and wherein the expandable channel is welded to the receiving notches of the first and second base plates when the expandable channel is in the second configuration.
 42. The apparatus as recited in claim 35 further comprising centralizers positioned in the annulus such that the second tubular is substantially concentric with the first tubular.
 43. A gravel packing apparatus assembled by the method as recited in claim
 1. 44. A gravel packing apparatus assembled by the method as recited in claim
 9. 45. A gravel packing apparatus assembled by the method as recited in claim
 17. 46. A gravel packing apparatus assembled by the method as recited in claim
 23. 47. A gravel packing apparatus assembled by the method as recited in claim
 28. 